What's the deal with Unleaded 88?

[TiGeo]

As you might have read above e15 is rarely more than 12% ethanol
Just as e10 is rarely more than 7% ethanol

I test Sheetz ethanol fuels regularly as well as the regular gas - E10 and E85 are typically right on the money so no reason to think that the 88 stuff is 15%.

Folks really get worked up over 5% more e than normal fuel. The concerns with E in a modern car aren't to do with the seals etc. like you hear, that's v. old vehicles at this point...it's in the fuel delivery system being able to delivery the volume necessary b/c you use a lot more ethanol vs. regular gas to get the same AFR. Vehicles rated as "flex fuel" don't have anything magic beyond a fuelling system (pumps, and a flex sensor to tell the ECU how to deal with it) to run it. A modern vehicle running 5% more E isn't going to get anywhere close to taxing the fuel system w/r to providing enough volume.

 

[Rand]

I test Sheetz ethanol fuels regularly as well as the regular gas - E10 and E85 are typically right on the money so no reason to think that the 88 stuff is 15%.

Not in my experience locally but will report back with photos after I go through my stash of 30gal "free" e10 gas.

I use "free" because it was 1800 reward points ($36 redemption food value) for 30 gallons on Black friday.

Had to buy 30gallons anything less was leaving "free" gas.. so Got a few cans out of the shed.

I was surprised how low the ethanol content at sheetz was..(e15) I figured the gas pump/storage had some sort of ethanol sensor for the blender pumps.

 

[Astro14]

As you might have read above e15 is rarely more than 12% ethanol
Just as e10 is rarely more than 7% ethanol

I understand the actual composition of the fuel - and my truck is flex-fuel - that’s very different. I have run that on e85 many times.

But since the pump won’t actually tell me if the E15 is above 10% ethanol on that day, do I fill my tank with something that is specifically prohibited by the manufacturer?

On the basis of “advice” from Internet forum posts?

Since I don’t know the reason for the prohibition- I won’t put e15 in a car where it is specifically stated not to.

 

[MNgopher]

I see, so if the state says it is OK, but the owner’s manual says this:

View attachment 190317

Specifically stating that you cannot use fuel that exceeds 10% oxygenate, including ethanol - Go with what the state tells you?

Ignoring the specific guidance of the manufacturer?

Do you also do what the state tells you for an oil change interval?

Ah, the owners manual that every BITOG owner follows to the letter for oil change viscosity, API service classifications, intervals, and manufacturer specifications.

Its funny how this board in some cases uses the owners manual as the gospel in some cases, but conveniently chooses not to follow it when it meets whatever case is the pet favorite.

Kind of like 5W20 when it came out and was back specified into many vehicles. The owners manuals often kept old language when new products and specs came out. Many manuals weren't updated for quite some time.

E15 was approved for 2008 and newer model years in 2010, and 2001 to 2007 model years in 2011. Here we are 12 years later still debating whether it should be used or not.

 

[Astro14]

Ah, the owners manual that every BITOG owner follows to the letter for oil change viscosity, API service classifications, intervals, and manufacturer specifications.

Its funny how this board in some cases uses the owners manual as the gospel in some cases, but conveniently chooses not to follow it when it meets whatever case is the pet favorite.

Kind of like 5W20 when it came out and was back specified into many vehicles. The owners manuals often kept old language when new products and specs came out. Many manuals weren't updated for quite some time.

E15 was approved for 2008 and newer model years in 2010, and 2001 to 2007 model years in 2011. Here we are 12 years later still debating whether it should be used or not.

That same manual says to run 10,000 mile intervals and use only an MB 229.5 oil.

Which I do.

Look, taking advice from people who don’t own the same kind of car, when that advice is contrary to the very specific prohibition in the manual, is not something I am interested in doing.

Folks who suggest “it will be fine” would have a lot more credibility if they drove a car with the same engine, and had actual experience with E15 on that engine/chassis combo. Absent that, it’s just another opinion without any actual experience to back it up.

I'm not willing to bet the performance, or risk a repair, on a complex car, that already has maintenance challenges, on the opinion of someone with no experience on that car.

Not when the manufacturer comes right out and says, "Don't do that".

 

[Rand]

Not when the manufacturer comes right out and says, "Don't do that".

My only question would be when did the manufacturer come out and say "don't do that"

Or did they possibly carry over 90% of the manual for 10 years like subaru.

I bet they couldnt get most people in the UK to use 10% Ethanol either It says not to in the manual!

 

[kschachn]

Ah, the owners manual that every BITOG owner follows to the letter for oil change viscosity, API service classifications, intervals, and manufacturer specifications.

Its funny how this board in some cases uses the owners manual as the gospel in some cases, but conveniently chooses not to follow it when it meets whatever case is the pet favorite.

Kind of like 5W20 when it came out and was back specified into many vehicles. The owners manuals often kept old language when new products and specs came out. Many manuals weren't updated for quite some time.

E15 was approved for 2008 and newer model years in 2010, and 2001 to 2007 model years in 2011. Here we are 12 years later still debating whether it should be used or not.

There is quite a difference in an oil grade recommendation based on CAFE requirements or using an oil with more stringent approval requirements and a prohibition against E15. One is technical, one is not.

So who approved the use of E15 in a Mazda where the owner’s manual says no?

 

[MNgopher]

There is quite a difference in an oil grade recommendation based on CAFE requirements or using an oil with more stringent approval requirements and a prohibition against E15. One is technical, one is not.

So who approved the use of E15 in a Mazda where the owner’s manual says no?

Maybe another questions is why Mazda continued with this language as long as they did when they knew they were selling cars into an environment that considers Regular Unleaded, E10, and E15 all to be "equivalent" for use in cars post 2001? Other manufacturers adopted the language and approved it much earlier (say Ford, Circa model year 2013). Its been the EPA standard since 2010 anyways... Yes, 13 years ago.

Kind of like OPE manufacturers selling junk components into an environment that has used that fuel forever, but blaming it on the "bad fuel"...

 

[kschachn]

Maybe another questions is why Mazda continued with this language as long as they did when they knew they were selling cars into an environment that considers Regular Unleaded, E10, and E15 all to be "equivalent" for use in cars post 2001? Other manufacturers adopted the language and approved it much earlier (say Ford, Circa model year 2013). Its been the EPA standard since 2010 anyways... Yes, 13 years ago.

Kind of like OPE manufacturers selling junk components into an environment that has used that fuel forever, but blaming it on the "bad fuel"...

Yes but the constant OPE complaints are about E10 (which the manuals allow), not E15. Don’t they also prohibit the use of E15?

Bottom line there is no real requirement that anyone allow E15, just as there is no requirement for flex-fuel.

 

[Hall]

Its funny how this board in some cases uses the owners manual as the gospel in some cases, but conveniently chooses not to follow it when it meets whatever case is the pet favorite.

Pick and choose

 

[Astro14]

My only question would be when did the manufacturer come out and say "don't do that"

Or did they possibly carry over 90% of the manual for 10 years like subaru.

I bet they couldnt get most people in the UK to use 10% Ethanol either It says not to in the manual!

It is the kind of company that is particular about details. They do update information quite regularly, often in the same model year, new manuals and service data are published.

My 2005 owners manual was quite clear in the screenshot. By 2015, the last year of that engine, the list of prohibited fuels was expanded, and E10 was still allowed. But higher ethanol, or methanol, content was still prohibited.

As a data point, in 2020, the S-class (now with a different engine) still prohibited E15.

And E15 was specifically called out, below.

Until one of you guys owns a similar car, and runs it on E15, for a considerable period, without issue, I think I’ll stick with Mercedes guidance.

 

[kschachn]

Pick and choose

Actually it’s called “understanding”. You only pick and choose if you don’t have any understanding.

 

[Cujet]

Engines can vary greatly in the ability to efficiently combust mixtures that are less than ideal. Everyone's least favorite engine, the Ford 3 valve, 5.4L has the remarkable ability to operate efficiently at mixtures as lean as 21 to 1. (pure gas of course). This does translate into proper, smooth operation with ethanol diluted fuel. Sure the ECU adjusts for any mixture up to E-85, but there is some other magic at play here. Maybe the very long stroke, and small bore, odd combustion chamber shape, and air/fuel tumble during the intake stroke.

Additionally, some engines (not the 5.4L) can achieve world class "diesel like" thermal efficiency on ethanol fuels.

In general, many conventional engines lose more "MPG" than the energy content loss of ethanol would suggest. Even so, there are engines where modest ethanol content percentage produces no real difference in the MPG provided.

Short of searching for elusive results for your make and model, might as well try it and see.

 

[Rand]

well the good news is e15 isnt being shoved up anyones rear yet.. unlike E10.

Until one of you guys owns a similar car

That seems pretty clear in that application.
Of course in that application would 88 octane even meet the requirement?
I wouldn't hold your breath on me buying S-Class. Check back if you are considering a 2020 Elantra.


I'm not a super 88 proponent. I do like that sheetz puts it on sale often and if your car allows... you save a few bucks.

Edit: for clarity

 

[Hall]

Actually it’s called “understanding”. You only pick and choose if you don’t have any understanding.

No, some people "pick" things they like and "choose" to ignore other things.

 

[Astro14]

No, some people "pick" things they like and "choose" to ignore other things.

I’m not one of those.

If the manufacturer is clear - I follow that guidance, be it operating or maintenance requirements.

I deviate from guidance only when testing and data allow me to do so safely.

I have no way of knowing why Mercedes stipulated that restriction on the twin turbo 3 valve engine.

Regardless, they’re also quite clear that it should be higher octane anyway. So, I wouldn’t use this stuff even if it were approved.

Absent a means for testing fuel system compatibility, component durability, combustion stability, dynamic air fuel ratio and a few other things to know (not guess, not suppose, not rely on the internet assurances of people who have no experience with the particular engine or fuel system) that I’m not causing harm - I will stick with the manufacturer recommendation.

 

[Delta]

I'm not a super 88 proponent. I do like that sheetz puts it on sale often and if your car allows... you save a few bucks.

The Sheetz near me regularly has E15 for $2.99 a gallon compared to 87 E10 which hovers around $3.63 to $3.75.

I did treat my truck the other day to 90 octane ethanol free to make up for the couple tanks of the 15% ethanol Sheetz stuff.

 

[Astro14]

Let me also be clear - I would fill up the Tundra all day long on E15 fuel at that price.

The truck is built for that.

I bought the flex fuel intentionally to allow for just these sorts of opportunities…and to future proof against some other fuel blend.

 

[TiGeo]

https://www.researchgate.net/publication/283721687_Review_and_Evaluation_of_Studies_on_the_Use_of_E15_in_Light-Duty_Vehicles

 

[TiGeo]